R4 — Use BLS business-survival data to decompose "dead site" causes — many are dead businesses, not platform failure

Rule: When reasoning about "site death" rates, first decompose by business survival using BLS Business Employment Dynamics — ~20–22% of US establishments fail Y1; ~49.6% five-year survival; ~65% failed by Y10. Roughly half of any SMB cohort is gone by year 5 regardless of platform.

Why: Attributing all dead sites to platform failure overstates the platform's role. The honest baseline is that ~50% of underlying businesses are gone by year 5 — any platform-attributable death rate sits on top of that floor.

How to apply: In comparing platforms, the relevant question is "what is the excess site-death rate beyond what BLS business-survival predicts?" — not "what fraction of sites die?"